Hu Hong-Zhen, Gao Na, Liu Sumei, Ren Jun, Wang Xiyu, Xia Yun, Wood Jackie D
Department of Physiology and Cell Biology, College of Medicine and Public Health, The Ohio State University, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA.
J Pharmacol Exp Ther. 2004 Apr;309(1):320-7. doi: 10.1124/jpet.103.059188. Epub 2004 Jan 12.
Intracellular recording methods with "sharp" microelectrodes were used to study actions of bradykinin (BK) on electrical behavior of morphologically identified neurons and the identification and localization of BK receptors in the submucosal plexus of guinea pig small intestine. Exposure to BK depolarized the membrane potential and elevated excitability in submucosal neurons with AH-type electrophysiological behavior and Dogiel II multipolar morphology and in neurons with S-type electrophysiological behavior and uniaxonal morphology. BK-evoked depolarizing responses were associated with increased neuronal input resistance in AH-type neurons and decreased input resistance in S-type neurons. The selective B(2) BK receptor antagonists HOE-140 (icatabant acetate) and WIN64338 [(S)-4[2-bis(cyclohexylamino)methyleneamino]-3-(2-napthalenyl)-1-oxopropylamino]benzyl tributyl phosphonium chloride hydrochloride], but not the selective B(1) receptor antagonists des-arg(10)-HOE-140 and des-arg(9)-leu(8)-BK, suppressed the BK-evoked responses. The selective B(2) receptor agonist Kallidin, but not the selective B(1) receptor agonist des-arg(9)-BK mimicked the excitatory action of BK. Western blot analysis and reverse transcription-polymerase chain reaction confirmed the expression of B(2) receptor protein and mRNA. Binding studies with a fluorescently labeled BK(2) antagonist found expression of B(2) receptors on a majority of the ganglion cells. B(2) receptors occupied 82% of the neurons that expressed immunoreactivity for neuropeptide Y, 75% of the neurons that expressed vasoactive intestinal peptide, 84% of the neurons that expressed substance P, 71% of the neurons that expressed choline acetyltransferase, and all neurons that expressed calbindin immunoreactivity. The results suggest that the B(2) receptor mediates the excitatory action of BK on submucosal plexus neurons. Pathophysiological significance of the excitatory actions on secretomotor neurons might be stimulated mucosal secretion and the secretory diarrhea associated with intestinal inflammatory states.
采用“尖锐”微电极的细胞内记录方法，研究缓激肽（BK）对形态学鉴定的神经元电活动的作用，以及BK受体在豚鼠小肠黏膜下神经丛中的鉴定和定位。暴露于BK使具有AH型电生理行为和Dogiel II型多极形态的黏膜下神经元以及具有S型电生理行为和单轴形态的神经元的膜电位去极化并提高其兴奋性。BK诱发的去极化反应与AH型神经元的神经元输入电阻增加以及S型神经元的输入电阻降低有关。选择性B(2) BK受体拮抗剂HOE-140（醋酸艾替班特）和WIN64338 [（S）-4[2-双（环己基氨基）亚甲基氨基]-3-（2-萘基）-1-氧代丙基氨基]苄基三丁基氯化铵盐酸盐]，而非选择性B(1)受体拮抗剂去-精氨酸(10)-HOE-140和去-精氨酸(9)-亮氨酸(8)-BK，抑制了BK诱发的反应。选择性B(2)受体激动剂胰激肽，而非选择性B(1)受体激动剂去-精氨酸(9)-BK，模拟了BK的兴奋作用。蛋白质印迹分析和逆转录-聚合酶链反应证实了B(2)受体蛋白和mRNA的表达。用荧光标记的BK(2)拮抗剂进行的结合研究发现，大多数神经节细胞上表达B(2)受体。B(2)受体占据了82%对神经肽Y呈免疫反应性的神经元、75%表达血管活性肠肽的神经元、84%表达P物质的神经元、71%表达胆碱乙酰转移酶的神经元以及所有表达钙结合蛋白免疫反应性的神经元。结果表明，B(2)受体介导了BK对黏膜下神经丛神经元的兴奋作用。对分泌运动神经元兴奋作用的病理生理意义可能是刺激黏膜分泌以及与肠道炎症状态相关的分泌性腹泻。
